1. In a food processor, finely chop the pecans. Next, add the basil, parmesan or miso, garlic, red pepper flakes (if using), and salt, and process very briefly.
2. Slowly add the olive oil in a steady stream and process for about 10 more seconds. You don't want a mushy paste here - some "graininess" and separation is perfect.
This pesto will keep in the fridge, surface covered with plastic wrap, for about 5-7 days. You can also freeze it -just scoop the pesto into ice cube tray compartments until frozen, and then transfer the pesto cubes to a freezer bag.
Some ideas:
I use two or three "cubes" or about 1/4 cup per 1/2 pound pasta (which serves two adults). Add the thawed pesto, along with a bit of reserved cooking water to thoroughly coat the pasta just before serving.
This pesto is great with grilled summer squash, such as zucchini and patty pans - brush it on just after grilling.
You might also swirl a bit of this pesto into servings of a broth-type soup just before presentation, if you want to be a super fancy pants and impress your foodie friends.